Flat Roofing Cambridge & Cambridgeshire

EPDM (ethylene propylene diene monomer) is a synthetic rubber membrane supplied in large, seamless sheets. We install the Firestone RubberCover system — one of the most widely used and trusted EPDM products in the UK. Its key advantages over traditional felt are its dramatically reduced number of seams (meaning fewer potential failure points), its exceptional flexibility (it accommodates structural movement without cracking), its resistance to UV degradation and temperature extremes, and its very long service life. It is also fully recyclable at end of life. For most domestic flat roof applications across Cambridge and Cambridgeshire — extensions, garages, outbuildings, bungalow flat roofs — EPDM represents the best balance of performance, longevity and value. The Firestone system specifically carries a 20-year product warranty, which we pass on to every customer.

This depends on the system, the age of the roof and the nature and extent of the failure. A single split seam, a lifted edge trim, a failed outlet or a localised blister on an otherwise sound membrane can often be repaired economically. A roof with widespread blistering, multiple leak points, a deteriorated deck or a system that is beyond its service life is generally better replaced — because repeated patch repairs on a failing system cost more over five years than a single replacement that lasts 40. We will give you an honest, evidence-based assessment of which route is appropriate during the free survey — with photographs to back up our recommendation. We will never recommend a replacement to inflate a job when a repair will provide a lasting fix.

Yes — flat roofs are one of the most common and practical choices for single-storey rear and side extensions across Cambridge and Cambridgeshire, and they are significantly more cost-effective to build than a matching pitched roof. Modern flat roofing systems — particularly EPDM rubber — are highly durable and weathertight, and the old reputation of flat roofs as unreliable largely relates to traditional three-layer felt systems installed decades ago. A correctly specified and properly installed modern flat roof on an extension will typically outlast the extension itself with minimal maintenance. We work on extension flat roofs across Cambridgeshire regularly and will recommend the right system and specification for your specific project during the survey.

Flat roof costs vary depending on the size of the roof, the system specified, the condition of the existing deck, the complexity of the detailing (number of upstands, penetrations, outlets) and any associated work such as insulation upgrades or guttering. A straightforward garage flat roof replacement in EPDM is typically a few hundred to low thousands; a full extension flat roof will depend on its size and specification; a large bungalow roof will be significantly higher. The only accurate figure is one based on a proper site survey and detailed measurement. We provide free surveys and written, fixed-price quotations — call 01223 859867 (Cambridge) or 01480 877624 (St Neots) to arrange yours.

Like-for-like flat roof replacement — replacing an existing flat roof with a new system at the same level and within the same footprint — generally falls within permitted development and does not require planning permission. However, if your property is within a Conservation Area (which covers parts of Cambridge city centre and several Cambridgeshire villages), or is a Listed Building, certain changes may require prior approval. If you are adding a flat roof where there was previously a pitched roof, or raising the parapet height, planning permission may also be required. We advise on any planning considerations we are aware of during the quotation process. When in doubt, check with Cambridge City Council or South Cambridgeshire District Council before any work begins.

Standing water (ponding) on a flat roof is almost always caused by insufficient falls — the gradient across the roof surface that directs water to the drainage outlets. All flat roofs require a minimum fall of 1:80 (approximately 12mm per metre run) to drain properly. If the roof was built without adequate falls, or if the deck has deflected over time and the falls have been lost, water will sit on the surface after rain. Ponding accelerates the deterioration of every flat roofing system and should not be ignored. Call us for an inspection — we will assess the falls, check the drainage outlets and advise on whether the issue can be corrected within a repair or whether it needs to be addressed as part of a replacement.

These terms describe how the insulation is positioned within the flat roof build-up. In a cold roof, insulation is placed between the ceiling joists below the deck — the deck itself is cold (uninsulated), with ventilation provided above the insulation to prevent condensation. In a warm roof, insulation is placed above the deck but below the membrane — the deck is kept at a warm temperature, eliminating the condensation risk and the need for ventilation. Warm roof construction is now the preferred specification for most new flat roof installations as it provides better thermal performance and is less prone to condensation problems. An inverted roof (a variant of the warm roof) places the insulation above the waterproof membrane for added protection of the membrane layer. We will specify the most appropriate build-up for your project and budget during the survey stage.